20662-89-9Relevant articles and documents
PdII-Catalyzed Regio- and Enantioselective Oxidative C?H/C?H Cross-Coupling Reaction between Ferrocenes and Azoles
Cai, Zhong-Jian,Liu, Chen-Xu,Gu, Qing,Zheng, Chao,You, Shu-Li
supporting information, p. 2149 - 2153 (2019/01/24)
Asymmetric C?H bond functionalization reaction is one of the most efficient and straightforward methods for the synthesis of optically active molecules. Herein we disclose an asymmetric C?H/C?H cross-coupling reaction of ferrocenes with azoles such as oxazoles and thiazoles. Palladium(II)/monoprotected amino acid (MPAA) catalytic system which exhibits excellent reactivity and regioselectivity for oxazoles and thiazoles. This method offers a powerful strategy for constructing planar chiral ferrocenes. Mechanistic studies suggest that the C?H bond cleavage of azoles is likely proceeding through a SEAr process and may not be a turnover limiting step.
Synthesis of Triarylpyridines in Thiopeptide Antibiotics by Using a C-H Arylation/Ring-Transformation Strategy
Amaike, Kazuma,Itami, Kenichiro,Yamaguchi, Junichiro
supporting information, p. 4384 - 4388 (2016/03/22)
We have described a C-H arylation/ring-transformation strategy for the synthesis of triarylpyridines, which form the core structure of thiopeptide antibiotics. This synthetic method readily gave 2,3,6-triarylpyridines in a regioselective manner by a two-p
Facile structural elucidation of imidazoles and oxazoles based on NMR spectroscopy and quantum mechanical calculations
Weitman, Michal,Lerman, Lena,Cohen, Shmuel,Nudelman, Abraham,Major, Dan T.,Gottlieb, Hugo E.
scheme or table, p. 1465 - 1471 (2010/04/04)
The reaction of 1,2,3-tricarbonyl derivatives with hexamethylenetetramine and ammonium acetate in acetic acid provides an unambiguous approach to the synthesis of imidazoles, whereas the Bredereck reaction of α-haloketones in formamide, yields both imidazoles and oxazoles. Herein we describe a facile methodology for distinguishing between these heterocyclic compounds based on a combination of NMR spectroscopy and quantum mechanical calculations. In the NMR data the oxazole C-2 has a chemical shift of ca. 150 ppm whereas in the imidazoles it is found at ca. 135 ppm, with a 1JC-H of ca. 250 Hz for the oxazoles and ca. 210 Hz for the imidazoles. 1JC-H values can be easily obtained from a gated-decoupled 13C spectrum, and even more trivially, from the separation of the H-2 13C satellites in the 1H spectra. Additionally, the computed NMR data, obtained from density functional theory, are found to be in good agreement with the experimental data and serve as valuable tools in identifying the products of the Bredereck reaction.
